Gate-tunable exchange bias effect in FePS3-Fe5GeTe2 van der Waals heterostructures

TL;DR

This study demonstrates electrically tunable exchange bias effects in a van der Waals heterostructure of FePS3 and Fe5GeTe2, using protonic gating to control interlayer magnetic coupling, advancing spintronics applications.

Contribution

First realization of electrically controlled exchange bias in vdW AFM-FM heterostructures via proton intercalation, enabling magnetic property tuning with gate voltage.

Findings

EB effects depend on ferromagnetic layer thickness.

Protonic gating modulates exchange coupling and magnetic configurations.

EB field reaches 23% of coercive field, with T_b > 50 K at Vg= -3.15 V.

Abstract

Electrical gate-manipulated exchange bias (EB) effect is a long-term goal for spintronics applications. Meanwhile, the emergence of van der Waals (vdW) magnetic heterostructures provides ideal platforms for the study of interlayer magnetic coupling. However, to date, the electrical gate-controlled EB effect has yet to be realized in vdW heterostructures. Here, for the first time, we realized electrically-controllable EB effects in a vdW antiferromagnetic (AFM)-ferromagnetic (FM) heterostructure, FePS3-Fe5GeTe2. For pristine FePS3-Fe5GeTe2 heterostructures, sizable EB effects can be generated due to the strong interface coupling, which also depend on the thickness of the ferromagnetic layers. By applying a solid protonic gate, the EB effects can be electrically tuned largely by proton intercalations and deintercalations. The EB field reaches up to 23% of the coercive field and the blocking temperature exceeds 50 K at Vg= -3.15 V. The proton intercalations not only tune the average magnetic exchange coupling, but also change the AFM configurations and transform the heterointerface between an uncompensated AFM-FM interface and a compensated AFM-FM interface. These alterations result in a dramatic modulation of the total interface exchange coupling and the resultant EB effects. The study is a significant step towards vdW heterostructure-based magnetic logic for future low-energy electronics.